Mixing apparatuses and pelleters, in particular carbon black pelleters, are known in the art. Pinned shafts rotatably arranged in housings have been described for these purposes. It is also known to employ two shafts arranged parallel in a housing, each shaft being provided with groups of pins arranged in straight lines, in a comb-like arrangement, with these combs interdigitating while the shafts are rotated. Such an apparatus is described, for instance, in U.S. Pat. No. 3,751,543. These comb-like structures cause power surging of the mechanism driving the shafts.
Other pelleting apparatuses utilize a plurality of pinned shafts arranged horizontally on top of each other with alternating right hand and left hand flights of partial double helices. Such an apparatus is, for instance, described in U.S. Pat. No. 2,828,191. In this apparatus at any given axial location the pin movement is always in the same direction, i.e. either from left to right or from right to left.